Sciencemadness Discussion Board

Hydrazine sulphate with sodium bisulphate

Keras - 28-12-2022 at 01:21

Folks,

the traditional way to get hydrazine sulphate is to mix sulphuric acid with the products of the Hoffman rearrangement.

However, since sulphuric acid has become quite tedious to find (at least over here in Europe), I suppose substituting it with a solution of sodium bisulphate, which is on tap, is a better option?

karolus28 - 28-12-2022 at 11:51

One would probably end up with a lot of sodium sulfate contamination when crystalising out the product. In theory adding enough hydrochloric acid would make Hydrazine Dihydrochloride and it should be possible to crystalise it out with cooling(some websites say it's solubility is 5g/100g @idk *C, cuz they didnt write that), though I assume the yield would suck ass

Σldritch - 29-12-2022 at 03:15

I have process in hydrazine sticky for you (using Calcium Hypochlorite, Sodium Bisulfate, Urea). You have my permission to copy the wierd letter in my username into the forum search engine bar.

Keras - 31-12-2022 at 00:05

Quote: Originally posted by Σldritch  
I have process in hydrazine sticky for you (using Calcium Hypochlorite, Sodium Bisulfate, Urea). You have my permission to copy the wierd letter in my username into the forum search engine bar.


The sigma? Ok, thanks.

Keras - 31-12-2022 at 00:09

Quote: Originally posted by karolus28  
One would probably end up with a lot of sodium sulfate contamination when crystalising out the product. In theory adding enough hydrochloric acid would make Hydrazine Dihydrochloride and it should be possible to crystalise it out with cooling(some websites say it's solubility is 5g/100g @idk *C, cuz they didnt write that), though I assume the yield would suck ass


Well, solubility of hydrazine sulphate is given as 30 g/L whereas that of sodium sulphate is around 300 g/L at 25 °C (and increases slightly with temperature). I’ll have to juggle with those figures to see what yield of almost pure product can be extracted.

Σldritch - 31-12-2022 at 01:43

BTW using Calcium Hypochlorite you save even more acid because you can just filter off the Calcium Carbonate. And to be clear I used hydrochloric acid AND Sodium Bisulfate. It was a while ago though so I can't really remember the details. You are better of checking my notes in the thread. IIRC I got 25% yield or so without gelatin and only using tap water. It is really very low tech. And it has worked every time for me - just don't cool it down too much or you'll get Sodium Sulfate.

Keras - 31-12-2022 at 10:11

Quote: Originally posted by Σldritch  
BTW using Calcium Hypochlorite…


OK. Fine, I've got quite a lot of it. It’s quite messy to work with, though, especially because it is never pure.

I’ll check your notes, thanks for pointing me to them! And happy new year!